Intracellular kinases play important functions in cells of the immune system. For example, interleukin-2 inducible tyrosine kinase (ITK) plays a key role in T cell development and differentiation; it regulates IL-2 production via phospholipase Cγ1 (PLCγ1) and nuclear factor of activated T cells (NFAT); it mediates Th2 cell differentiation; and it regulates T cell migration and recruitment to lymphatic organs. Bruton's tyrosine kinase (BTK) is involved in signal transduction pathways which regulate growth and differentiation of B lymphoid cells. BTK also is involved in platelet physiology by regulating the glycoprotein VI/Fc receptor γ chain (GPVI-FcRγ)-coupled collagen receptor signaling pathway. For these reasons, inhibitors of intracellular kinases are useful for treating blood cell malignancies, solid tumors and for suppressing the immune system, for example in patients with autoimmune disorders or organ transplants. Intracellular kinase inhibitors also are useful for preventing or reducing the risk of thromboembolism.